In the LTE system of the 3GPP specification, which is one of radio communication specifications, a mobile terminal (UE) controls a transmission power based on a TPC command transmitted from a base station (eNB) in an uplink communication between the eNB and the UE. The 3GPP is an abbreviation for the third generation partnership project, and the LTE is an abbreviation for the long term evolution. The eNB is an abbreviation for the evolved node B, the UE is an abbreviation for the user equipment, and the TPC is an abbreviation for the transmission power control.
In other words, the UE is controlled in a closed loop, and a transmission power (physical uplink shared channel (PUSCH) transmission power) of the uplink data transmission is controlled based on an cumulative value of offset values specified by a TPC command transmitted from the eNB.
In radio communication systems such as a recent mobile phone network, an examination is in progress on a heterogeneous network where a small base station forming a small radio cell (radio area) called a femtocell area is disposed in a general home and office. By installing a femtocell base station, a femtocell area is formed within an area of an outdoor macro cell, and thereby quality improvement of indoor mobile phone services and expansion of the service area are expected. Further, a radio traffic offload effect in an outdoor macro cell base station is expected. Related techniques are disclosed in, for example, Japanese National Publication of International Patent Application No. 2008-529375, International Publication Pamphlet No. WO 2009/72178, and Japanese Laid-open Patent Publication Nos. 2007-151167 and 2011-166435.